1 files changed, 50 insertions, 11 deletions

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 033feeab8c34..8059ece82468 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -28,6 +28,7 @@
 #include <linux/mm.h>
 #include <linux/pagemap.h>
 #include <linux/gfp.h>
+#include <linux/rmap.h>
 #include <linux/swap.h>
 #include <linux/compaction.h>
 
@@ -207,24 +208,25 @@ nfs_file_splice_read(struct file *in, loff_t *ppos, struct pipe_inode_info *pipe
 EXPORT_SYMBOL_GPL(nfs_file_splice_read);
 
 int
-nfs_file_mmap(struct file *file, struct vm_area_struct *vma)
+nfs_file_mmap_prepare(struct vm_area_desc *desc)
 {
+	struct file *file = desc->file;
 	struct inode *inode = file_inode(file);
 	int	status;
 
 	dprintk("NFS: mmap(%pD2)\n", file);
 
-	/* Note: generic_file_mmap() returns ENOSYS on nommu systems
+	/* Note: generic_file_mmap_prepare() returns ENOSYS on nommu systems
 	 *       so we call that before revalidating the mapping
 	 */
-	status = generic_file_mmap(file, vma);
+	status = generic_file_mmap_prepare(desc);
 	if (!status) {
-		vma->vm_ops = &nfs_file_vm_ops;
+		desc->vm_ops = &nfs_file_vm_ops;
 		status = nfs_revalidate_mapping(inode, file->f_mapping);
 	}
 	return status;
 }
-EXPORT_SYMBOL_GPL(nfs_file_mmap);
+EXPORT_SYMBOL_GPL(nfs_file_mmap_prepare);
 
 /*
  * Flush any dirty pages for this process, and check for write errors.
@@ -279,6 +281,37 @@ nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 }
 EXPORT_SYMBOL_GPL(nfs_file_fsync);
 
+void nfs_truncate_last_folio(struct address_space *mapping, loff_t from,
+			     loff_t to)
+{
+	struct folio *folio;
+
+	if (from >= to)
+		return;
+
+	folio = filemap_lock_folio(mapping, from >> PAGE_SHIFT);
+	if (IS_ERR(folio))
+		return;
+
+	if (folio_mkclean(folio))
+		folio_mark_dirty(folio);
+
+	if (folio_test_uptodate(folio)) {
+		loff_t fpos = folio_pos(folio);
+		size_t offset = from - fpos;
+		size_t end = folio_size(folio);
+
+		if (to - fpos < end)
+			end = to - fpos;
+		folio_zero_segment(folio, offset, end);
+		trace_nfs_size_truncate_folio(mapping->host, to);
+	}
+
+	folio_unlock(folio);
+	folio_put(folio);
+}
+EXPORT_SYMBOL_GPL(nfs_truncate_last_folio);
+
 /*
  * Decide whether a read/modify/write cycle may be more efficient
  * then a modify/write/read cycle when writing to a page in the
@@ -342,17 +375,20 @@ static bool nfs_want_read_modify_write(struct file *file, struct folio *folio,
  * If the writer ends up delaying the write, the writer needs to
  * increment the page use counts until he is done with the page.
  */
-static int nfs_write_begin(struct file *file, struct address_space *mapping,
+static int nfs_write_begin(const struct kiocb *iocb,
+			   struct address_space *mapping,
 			   loff_t pos, unsigned len, struct folio **foliop,
 			   void **fsdata)
 {
 	fgf_t fgp = FGP_WRITEBEGIN;
 	struct folio *folio;
+	struct file *file = iocb->ki_filp;
 	int once_thru = 0;
 	int ret;
 
 	dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
 		file, mapping->host->i_ino, len, (long long) pos);
+	nfs_truncate_last_folio(mapping, i_size_read(mapping->host), pos);
 
 	fgp |= fgf_set_order(len);
 start:
@@ -377,10 +413,12 @@ start:
 	return ret;
 }
 
-static int nfs_write_end(struct file *file, struct address_space *mapping,
+static int nfs_write_end(const struct kiocb *iocb,
+			 struct address_space *mapping,
 			 loff_t pos, unsigned len, unsigned copied,
 			 struct folio *folio, void *fsdata)
 {
+	struct file *file = iocb->ki_filp;
 	struct nfs_open_context *ctx = nfs_file_open_context(file);
 	unsigned offset = offset_in_folio(folio, pos);
 	int status;
@@ -437,10 +475,11 @@ static void nfs_invalidate_folio(struct folio *folio, size_t offset,
 	dfprintk(PAGECACHE, "NFS: invalidate_folio(%lu, %zu, %zu)\n",
 		 folio->index, offset, length);
 
-	if (offset != 0 || length < folio_size(folio))
-		return;
 	/* Cancel any unstarted writes on this page */
-	nfs_wb_folio_cancel(inode, folio);
+	if (offset != 0 || length < folio_size(folio))
+		nfs_wb_folio(inode, folio);
+	else
+		nfs_wb_folio_cancel(inode, folio);
 	folio_wait_private_2(folio); /* [DEPRECATED] */
 	trace_nfs_invalidate_folio(inode, folio_pos(folio) + offset, length);
 }
@@ -899,7 +938,7 @@ const struct file_operations nfs_file_operations = {
 	.llseek		= nfs_file_llseek,
 	.read_iter	= nfs_file_read,
 	.write_iter	= nfs_file_write,
-	.mmap		= nfs_file_mmap,
+	.mmap_prepare	= nfs_file_mmap_prepare,
 	.open		= nfs_file_open,
 	.flush		= nfs_file_flush,
 	.release	= nfs_file_release,